1. Field of the Invention
This invention relates to testing systems for wireless communication devices and more particularly to systems and methods for calibrating and testing integrated radio modules of wireless access devices.
2. Description of Related Art
The use of wireless communication devices for data networking continues to grow at a rapid pace. Data networks that use “WiFi” (“Wireless Fidelity”), also known as “Wi-Fi,” are relatively easy to install, convenient to use, and supported by the IEEE 802.11 standard. WiFi data networks also provide performance that makes WiFi a suitable alternative to a wired data network for many business and home users.
WiFi networks operate by employing wireless access points that provide users, having wireless (or “client”) devices in proximity to the access point, with access to varying types of data networks such as, for example, an Ethernet network or the Internet. The wireless access points include a radio that operates according to the standards specified in different sections of the IEEE 802.11 specification. Generally, radios in the access points communicate with client devices by utilizing omni-directional antennas that allow the radios to communicate with client devices in any direction. The access points are then connected (by hardwired connections) to a data network system that completes the access of the client device to the data network. The different standards under IEEE 802.11 define ‘channels’ that wireless devices, or clients, use when communicating with an access point.
Access points provide service to a limited number of users. Access points are assigned a channel on which to communicate. Some of the channels provided by different 802.11 standards overlap. Each channel allows a recommended maximum of 64 clients to communicate with the access point. In addition, access points must be spaced apart strategically to reduce the chance of interference, either between access points tuned to the same channel, or to overlapping channels. In addition, channels are shared. Only one user may occupy the channel at any give time. As users are added to a channel, each user must wait longer for access to the channel thereby degrading throughput.
Another degradation of throughput as the number of clients grow is the result of the use of omni-directional antennas. Certain access point technology may employ one or two radios in close proximity resulting in interference, which reduces throughput. In an example of a two radio access point, both radios may be utilized as access points (i.e., each radio communicates with a different client device) or one radio may function as the access point while the other radio functions as a backhaul, i.e., a communication channel from the access point to a network backbone, central site, and/or other access point. Typically, the interference resulting from the different antennas utilized with these radios limits the total throughput available and, as a result, reduces traffic efficiency at the access point.
High-end wireless devices recently developed include multiple radios to improve bandwidth, user density, signal strength, coverage area, signal management and load balancing. The development of these new wireless devices has resulted in the need for testing systems to calibrate and troubleshoot wireless communication hardware during development. Known testing systems may calibrate wireless communication devices in a wired fashion. As a result, accurate testing or calibration of the antennas of the wireless communication devices, in many instances, may not be accomplished. Accordingly, proper analysis of the operation of the antennas of the wireless communication devices may not result.
Thus, there is a need for a calibration and testing system that provides the ability to calibrate, test, and troubleshoot the integrated radio modules of wireless communication devices.